Automatic controls for well drills



July 12, 1960 o. w. LE GATE AUTOMATIC CONTROLS FOR WELL DRILLS Filed Sept. 28. 1959 s R Y P WT m r A 3 1 m w F M R M 8 0 4 m 6 H I 3 4 y w L J 3 a 7 f 0) H a 3 8 3 w 9 um d u w 2 K r I m u n n 7 a 5 5 7 w w United ta s Pa 1 airwaves AUTOMATIC coN'rRoLs ro WELL Dams Osborne l e Gate, '44 E. 14th St., Edmond, Okla. ma Sept. 28, 1959, ser. No. 842,819 2 Claims. or. 254-173 The present invention relates to automatic controls for well drills, and more particularly to vacuum-operated mechanism for controlling the advance of a rotary drilling tool into the ground. The control is responsive to the weight of the suspended drill pipe and is designed to insure, within desired limits, optimum pressure on the drill bit as it is lowered.

As the operation of drilling a well proceeds, the weight of the drill string or pipe becomes progressively greater, and, if not properly suspended and lowered, the pressure of the drill string on the drill bit will either be too great, resulting in rapid deterioration thereof, or too light to perform eflicient drilling. It is, therefore, an object of this invention so to control the feed of the drill bit that undue pressure thereon is avoided and, at the same time, the pressure imposed on the tool will be sufiicient to promote ideal drilling conditions.

Another object of the invention is to provide vacuumactuated brake releasing means for the conventional cable drum, these releasing means being responsive to a novel form of control valve which in turn is responsive to the weight imposed on the feed cable.

Other objects will be apparent from the following description when taken with the accompanying drawings in which I Fig. l is a diagrammatic view of the assembled components of the invention;

Fig. 2 is an elevationof a control valve and actuator therefor forming part of the apparatus;

,Pat enterl July 12, 1960 a brake actuator 39 through conduit 4 1. The brake actuator comprises a housing 42 divided into chambers bracket 53 in the casing 54. Leaf 51is provided with an aperture 55' normally out of register with the open" Fig. 3 is a fragmentary side view of the mechanism shown in Fig. 2; and

Fig. 4 is an elevation, .partly in section, of the vacuumoperated brake actuator.

Referring to Fig. 1 of the drawings, it will be seen that a vacuum pump 10 is in communication with a vacuum reservoir 11 through conduit 12, suitable controls (not shown) being associated therewith to maintain a desired degree of vacuum in the reservoir. Pipe 13 terminates in a T-coupling 14 to which is connected pipe 15 leading to control valve 16 and pipe 17 leading to vacuum-actuated relay motor 18. The relay motor comprises a housing 19 having a dividing wall 21 to form upper and lower chambers. Each of these chambers is likewise divided by diaphragms 22, 23 into upper chambers 24, 25 and lower chambers 26, 27. Pipe 28 connects vacuum line 17 with chamber 24 above the upper diaphragm 22. Line 17 also leads to a port 29 at the bottom of housing 19. Chamber 25 communicates with atmosphere through opening 31. Connected to dia- V phragm 22 is a stem 32 having a cage 33 secured to its lower end, the cage in turn being fastened to diaphragm' 23. Thus, it will be seen, the diaphragms are constrained to move together. Diaphragm 23 is provided with an opening 34, the periphery of which forms a seat for valve head 35. A second stem 36 connects valve head 35 with another valve head 37 adapted to cooperate with valve seat 38 above port 29. Chamber 26 communicates with control valve 16 and chamber 27 is connected to 43, 44 by diaphragm 45, the latter being normally held in brake-applying position by spring 46.

Referring to'Figs. 2 and 3, the control'valve 16 inopen end of which is normally closed by leaf 51 secured to the terminal end of Bourdon tube 52mounted in end of branch 49 so that, as long as this branch is not open to the atmosphere, both upper and lower chambers 24, 26 of the relay are in communication with reservoir 11. The position of coupling 47 may be adjusted by means of bell-crank 56 on which the coupling is mounted, adjustment thereof being efiected by screw 57 threaded infixed nut 58 in the casing 54, the screw abutting one arm of the bell-crank.

Bourdon tube 52 connects through conduit 59 with a weight-responsive fluid motor 61, this motor having a diaphragm or piston operatively connected by rod 62 and lever 63 to the dead end of cable 64. The cable is secured to a fixed portion of the derrick by a resilient connection such as spring 65 or the like. A suitable length of cable is wound on drum 66 and, by means of block 67 secured to the derrick, the cable suspends the drill string 68. .Brake 69 normally prevents the drum from rotating, but, when it is released, the weight of the drill string unwinds the cable until the brake is again applied. As long as the pressure on the drill bit is maintained within desired limits, the advance of the tool will be gradual. But if for any reason this pressure falls below these limits, the pull of the weight of the drill string will actuate the weight indicator or motor 61. Movement of the diaphragm or piston in this motor will then be transmitted through a suitable fluid to Bourdon tube 52 and leaf valve 51. Opening 55 will then register with conduit 49 permitting air at atmospheric. pressure to enter the lower chamber 26 of relay 18. Since the upper chamber 24 of the relay is in communication with the source of vacuum, diaphragm 22 will rise and elevate diaphragm 23 to a position Where valve head 35 will be engaged by valve seat 34 closing chamber 27 to atmospheric pressure. Further upward movement of diaphragm 23 raises both valve heads 35 and 37. When valve 37 is lifted from seat 38, the pressure in chamber 27 is lowered and, at the same time, chamber 43 in the brake actuating motor is placed in communication with the source of vacuum through conduit 41. Diaphragm 45 will then move connecting rod 71 upwardly and, through lever 72, will release brake 68 to permit the cable to unwind from drum 66. When the drill bit again encounters resistance, the pull of the weight of the drill string will be reduced and motor 61 will be reversed,

- thus returning leaf valve 51 to a position in which the branch conduit will be closed. Relay 18 will then be returned to its normal position with the pressures on opposite sides of the diaphragm being equalized. In this latter position of the relay diaphragms are lowered to seat valve 37 and unseat valve 35. A suitable air drain aperture 73 in the wall of lower chamber 44 is provided to permit the brake actuating diaphragm to return to brake applying position.

From the foregoing description it will be understood that controlled feed of the drill bit'may be regulated within desired limits and that regulation is readily effected by adjustment of the control valve. The application and releaseof the cable drum brake is elfectively controlled 3 by vacuum-actuated apparatus responsive to the weight of the drill string.

While a preferred embodiment of the invention has been illustrated and described, it is intended that modifications thereof are contemplated and may be employed without departing from the essential arrangement of component parts of the apparatus as expressed in the appended claims.

What is claimed is:

1. Automatic control apparatus for regulating the feed of a drilling string and associated tool comprising a drum, a cable wound on said drum and suspending said tool, a brake for said drum, a source of vacuum, vacuumactuated means communicating with said source for releasing said brake to unwind said cable, a relay valve for controlling the degree of vacu m applied to said 4 brake releasing means, a balanced vacuum-operated motor adapted to actuate said relay valve, and other valve means responsive to the weight of said drill string for modifying the pressures in said motor whereby said motor moves said valve to actuate said brake releasing means. 2. Automatic control apparatus as claimed in claim 1 in which said other valve means comprises an apertured w leaf having a portion normally closing said source of vacuum to atmosphere and movable to a position to open 10 said source to atmosphere.

References Cited in the file of this patent "UNITED STATES PATENTS AM A 

